156
7 Water and Wastewater Treatment
What is the significance of screening? How does water treatment contribute
to better water quality?
7.2 Preliminary Treatment
Many urban wastewater sewers have various ranges of matter, usually bulky,
particularly in combined systems. Preliminary treatment is crucial for protecting
systems and pipelines against blockages. Ideally, preliminary treatment involves
treating wastewater using industrial and commercial facilities to eliminate harmful
pollutants before discharging the water to a sewer system. For any waste to be
perceived as pre-treated, it should comply with the basic definition of treatment,
which entails meeting a three-point test (Neyens and Baeyens 2003). First, the water
should go through a specific process that involves chemical, biological, thermal,
or physical treatment. Second, the process should alter the waste’s characteristics.
Third, it should do so to minimize the volume of the waste, enhance its management,
minimize its hazardous nature, and improve its recovery. This implies that there is
a need to separate a part of each waste stream to facilitate recycling. Furthermore,
this process could be more complicated when technologies like anaerobic digestion
and mechanical biological treatment are used. There are two significant trends in
today’s modern plants. The first one is the minimization of by-products that must be
discharged outside the plant resulting in residual grease and grit treatment systems
(Qasim 2017). The second entails the need to establish an effective preliminary
treatment and part of a compact system. Ideally, pre-treatment is crucial for
removing all materials that can be collected easily from raw sewage before they
damage or clog primary treatment clarifiers. The major objects removed in this
phase are large objects, such as branches, leaves, and trash. The sewage material
goes through a bar screen to facilitate the removal of all the large objects that are
contained in the sewage stream (Qasim 2017). It is commonly carried out with a
mechanically raked bar screen in processing plants that serve large populations. The
design of the mechanical bar screen is such that it aligns with the flow rate. The
solids collected during this phase are often disposed of in landfills or occasionally
incinerated. If large solids remain in the waste stream, they can become entrained
within the treatment plant’s pipes and moving parts.
Briefly discuss the anaerobic digestion treatment (refer to Neyens and
Baeyens 2003).
Prior to primary treatment, preliminary treatment is carried out for grit removal,
flow equalization, and fat and grease removal. Grit is made up of heavy materials,
including sand, cinders, and gravel. It also consists of organic matter, including
7 Water and Wastewater Treatment
What is the significance of screening? How does water treatment contribute
to better water quality?
7.2 Preliminary Treatment
Many urban wastewater sewers have various ranges of matter, usually bulky,
particularly in combined systems. Preliminary treatment is crucial for protecting
systems and pipelines against blockages. Ideally, preliminary treatment involves
treating wastewater using industrial and commercial facilities to eliminate harmful
pollutants before discharging the water to a sewer system. For any waste to be
perceived as pre-treated, it should comply with the basic definition of treatment,
which entails meeting a three-point test (Neyens and Baeyens 2003). First, the water
should go through a specific process that involves chemical, biological, thermal,
or physical treatment. Second, the process should alter the waste’s characteristics.
Third, it should do so to minimize the volume of the waste, enhance its management,
minimize its hazardous nature, and improve its recovery. This implies that there is
a need to separate a part of each waste stream to facilitate recycling. Furthermore,
this process could be more complicated when technologies like anaerobic digestion
and mechanical biological treatment are used. There are two significant trends in
today’s modern plants. The first one is the minimization of by-products that must be
discharged outside the plant resulting in residual grease and grit treatment systems
(Qasim 2017). The second entails the need to establish an effective preliminary
treatment and part of a compact system. Ideally, pre-treatment is crucial for
removing all materials that can be collected easily from raw sewage before they
damage or clog primary treatment clarifiers. The major objects removed in this
phase are large objects, such as branches, leaves, and trash. The sewage material
goes through a bar screen to facilitate the removal of all the large objects that are
contained in the sewage stream (Qasim 2017). It is commonly carried out with a
mechanically raked bar screen in processing plants that serve large populations. The
design of the mechanical bar screen is such that it aligns with the flow rate. The
solids collected during this phase are often disposed of in landfills or occasionally
incinerated. If large solids remain in the waste stream, they can become entrained
within the treatment plant’s pipes and moving parts.
Briefly discuss the anaerobic digestion treatment (refer to Neyens and
Baeyens 2003).
Prior to primary treatment, preliminary treatment is carried out for grit removal,
flow equalization, and fat and grease removal. Grit is made up of heavy materials,
including sand, cinders, and gravel. It also consists of organic matter, including